In-Mold-Coated Automotive Interior and Other Products, and Methods for Manufacturing Same

ABSTRACT

Described are in-mold coated products such as vehicular components, in-mold coating methods, and in-mold coating compositions, involving the use of aqueous acrylic copolymer dispersions, desirably self-crosslinking.

The present application is a divisional of U.S. patent application Ser.No. 11/231,568 filed Sep. 21, 2005, pending, which is a continuation ofU.S. patent application Ser. No. 10/308,329 filed Dec. 3, 2002,abandoned, which claims the benefit of U.S. Provisional PatentApplication, Ser. No. 60/338,597 filed Dec. 3, 2001, each of which ishereby incorporated by reference in its entirety.

BACKGROUND

The present invention relates generally to in-mold-coated products suchas automotive interior articles including a decorative or protectivecoating atop an underlying foam, film or other plastic material. In oneparticular embodiment, the invention relates to an automotive interiorarticle prepared by in-mold coating, including a polyurethane substratecovered with an in-mold coating containing a water-dispersible,self-crosslinked acrylic polymer composition.

As further background, automotive interior articles such as instrumentpanels, door panels, armrests, headrests, floor consoles, knee bolsters,steering wheels, and glove compartment doors are often constructed byapplying a soft decorative covering over a rigid substrate mountable inan automobile vehicular body, with a cellular polyurethane paddinginterposed between the decorative covering and rigid substrate. Avariety of in-mold coating compositions and systems have been proposedfor use in preparing such automotive components. However, the coatingsystems proposed and used to date present a number of limitations. Forexample, many such systems require the use of solventborne compositions,which present environmental concerns relative to emissions. In addition,there is a trend to use polyurethane-based in-mold coatings to coverpolyurethane substrates because it is widely believed that such a systemis necessary for good adhesion of the decorative coating to thesubstrate.

In view of the background in this area, needs remain for improvedin-mold coating compositions, in-mold coating methods, andin-mold-coated automotive articles. The present invention addressesthese needs.

SUMMARY OF THE INVENTION

It has been discovered that highly advantageous in-mold coated articles,in-mold coating methods, and in-mold coating compositions can beprovided involving the use of aqueous acrylic copolymer dispersions,desirably self-crosslinking. Accordingly, one embodiment of the presentinvention provides a method for manufacturing a vehicular component,such as an automotive interior article, including a polymer substrateand a coating thereon, comprising the steps of providing a mold having amold surface, coating the mold surface with an aqueous, acryliccopolymer dispersion for forming said coating, passing into the mold amoldable polymer for forming the polymer substrate, and causing thecopolymer dispersion and moldable polymer to cure. Particularlypreferred embodiments of the invention involve the use of moldablepolyurethane-forming polymer compositions in combination with aqueousacrylic copolymer dispersions to form the coating on the polyurethanearticle.

Another preferred embodiment of the present invention provides avehicular component such as an automotive interior article that includesan inner polymer layer coated with an in-mold coating, wherein thein-mold coating is formed with an aqueous, acrylic copolymer dispersion,desirably a self-crosslinking acrylic copolymer dispersion.

Still another preferred embodiment of the present invention provides anin-mold coating composition for use in in-mold coating of vehicularcomponents such as automotive interior articles, wherein the in-moldcoating composition comprises an aqueous acrylic copolymer dispersion,desirably a self-crosslinking aqueous acrylic copolymer dispersion.

Another embodiment of the invention provides an elastomeric skin thatincludes a molded elastomeric polyurethane layer, and a coating formedin-mold with said elastomeric polyurethane layer and comprised of thereaction product of an aqueous acrylic copolymer dispersion.

Another embodiment of the invention provides a polyurethane productcomprising a molded polyurethane elastomer foam substrate, and a coatingadhered to the molded polyurethane elastomer foam substrate. The coatingis formed in-mold with the polyurethane elastomer foam substrate and iscomprised of the reaction product of an aqueous acrylic copolymerdispersion.

Another embodiment of the invention provides a method of manufacturing acoated, molded polyurethane elastomer product. The method includesproviding a mold for making a product, the mold having a mold surface;coating the mold surface with an in-mold coating composition, saidin-mold coating composition comprising a self-crosslinking, aqueouscopolymer dispersion; passing a polyurethane elastomer composition intothe mold and into contact with the in-mold coating composition; andcausing the in-mold coating composition and polyurethane elastomercomposition to cure, so as to form the coating for the vehicularcomponent.

It is an object of the invention to provide improved methods for formingautomotive interior articles and other similar vehicular components.

It is another object of the invention to provide improved, in-moldcoated automotive interior articles and other similar vehicularcomponents.

It is another object of the invention to provide improved in-moldcoating compositions.

These and additional objects, as well as features and advantages of theinvention will be apparent from the descriptions herein.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a cross-sectional view of an in-mold-coated steering wheel ofthe present invention.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

For the purposes of promoting an understanding of the principles of theinvention, reference will now be made to certain embodiments thereof andspecific language will be used to describe the same. It willnevertheless be understood that no limitation of the scope of theinvention is thereby intended, such alterations, further modificationsand further applications of the principles of the invention as describedherein being contemplated as would normally occur to one skilled in theart to which the invention relates.

As disclosed above, the present invention provides in mold coatingprocesses, in-mold coated products, including vehicular components suchas automotive interior products, and compositions for the same.Preferred processes and products of the invention utilize aqueous,acrylic-based coating compositions to coat cellular or non-cellularpolyurethane layers, surprisingly providing good adhesion of the coatingdirectly to the polyurethane layer, and a coating exhibiting propertiesmeeting stringent standards of the vehicular industries. Additionalin-mold-coated products of the invention include molded products otherthan vehicular components, such as toys, balls, seat cushion or armrestcushion coverings for wheelchairs, furniture or the like, or buildingmaterials (e.g. artificial stone or stone panels), formed from foamedpolyurethane compositions.

Preferred processes of the present invention will employ an in-moldcoating technique. Thus, a first mold component presenting a moldsurface will be employed. The first mold surface will define aconfiguration complementing the desired configuration of the outer layerof the automotive interior product. Typically, the mold surface will begrained to define a texture in the molded article, for example asimulated leather texture.

In accordance with the invention, a water-dispersed composition will beapplied, for example sprayed, onto the mold surface. Thiswater-dispersed composition will form a coating providing the outerlayer of the desired product. Prior to application of thewater-dispersed composition, the mold surface will usually be heated,for example to a temperature in the range of about 25° C. to about 110°C., more preferably about 40° C. to about 90° C. The selection of theparticular mold temperature will be dependent upon several factors,including for example the particular article to be manufactured andmanufacturing process, the properties of the water-dispersedcomposition, and the like. Given the disclosures herein, the selectionof a suitable mold temperature will be within the purview of thoseordinarily skilled in the art.

Processes of the invention may also employ compositions that facilitaterelease of the molded product from the mold, or so-called mold releaseagents. Such agents may include for example a microcrystalline wax, asilicon-based agent, or a stearate (each of these water- and/or organicsolvent-borne), and can optionally be applied to the mold surface priorto the water-dispersed composition. Heating of the mold surface may thenalso evaporate the wax dispersants and leave a thin residue that doesnot collect in the grain detail or other texturing pattern of the moldsurface.

Preferred processes of the invention will employ a water-dispersed oraqueous acrylic copolymerisate composition to form the outer layer ofthe automotive interior part. Preferred copolymerisate compositions willexhibit a core-and-shell structure. Suitable such compositions aredescribed, for example, in Canadian Patent Application No. 2,286,855published Apr. 19, 2001 (Vianova Resins Aktiengesellschaft).

Thus, particularly preferred compositions for forming the outer layerwill comprise aqueous self-crosslinking copolymer dispersions ABCobtainable by free-radically initiated copolymerization in the firststage of a monomer mixture A comprising mass fractions in the mixture of

-   A1 from 2 to 55%, preferably from 4 to 45% and, with particular    preference, from 6 to 40% of olefinically unsaturated monomers    having in each case at least one carbonyl group per molecule,-   A2 from 0.5 to 20%, preferably from 1 to 15% and, with particular    preference, from 3 to 12% of α,β-olefinically unsaturated carboxylic    acids or monoesters of α,β-olefinically unsaturated dicarboxylic    acids with linear, branched or cyclic alcohols having 1 to 15 carbon    atoms,-   A3 from 20 to 70%, preferably from 22 to 60% and, with particular    preference, from 24 to 50% of olefinically unsaturated monomers    selected from vinylaromatic compounds, n-butyl methacrylate and also    alkyl esters of α,β-olefinically unsaturated carboxylic acids or    dialkyl esters of α,β-olefinically unsaturated dicarboxylic acids,    the alkyl groups being selected from linear and branched alkyl    groups having up to 3 carbon atoms in the alkyl radical and cyclic    and polycyclic alkyl groups having 5 to 15 carbon atoms in the alkyl    group,-   A4 from 10 to 60%, preferably from 15 to 50% and, with particular    preference, from 20 to 45% of esters selected from alkyl esters of    α,β-olefinically unsaturated carboxylic acids or dialkyl esters of    α,β-olefinically unsaturated dicarboxylic acids, the alkyl groups    being selected from linear and branched alkyl groups having more    than 3 carbon atoms in the alkyl radical, with the exception of    n-butyl methacrylate, and-   A5 from 0 to 25%, preferably from 2 to 20% and, with particular    preference, from 5 to 15% of other free-radically polymerizable    monomers selected from vinyl esters of aliphatic saturated    carboxylic acids having 2 to 18 carbon atoms, hydroxyalkyl esters,    nitriles and amides of α,β-unsaturated carboxylic acids,    the sum of the mass fractions of components A1 to A5 necessarily    being 100%, and by subsequent addition of a second monomer mixture B    and further free-radically initiated polymerization of this monomer    mixture in the second stage, the mixture of B comprising mass    fractions of-   B1 from 30 to 90%, preferably from 40 to 80% and, with particular    preference, from 50 to 75% of olefinically unsaturated monomers    selected from vinylaromatic compounds, n-butyl methacrylate and also    alkyl esters of α,β-olefinically unsaturated carboxylic acids or    dialkyl esters of α,β-olefinically unsaturated dicarboxylic acids,    the alkyl groups being selected from linear and branched alkyl    groups having up to 3 carbon atoms in the alkyl radical and cyclic    and polycyclic alkyl groups having 5 to 15 carbon atoms in the alkyl    group,-   B2 from 10 to 60%, preferably from 20 to 50% and, with particular    preference, from 25 to 40% of esters selected from alkyl esters of    α,β-olefinically unsaturated carboxylic acids or dialkyl esters of    α,β-olefinically unsaturated dicarboxylic acids, the alkyl groups    being selected from linear and branched alkyl groups having more    than 3 carbon atoms in the alkyl radical, with the exception of    n-butyl methacrylate, and-   B3 from 0 to 40%, preferably from 5 to 30% and, with particular    preference, from 10 to 25% of other free-radically polymerizable    monomers selected from vinyl esters of aliphatic saturated    carboxylic acids having 2 to 18 carbon atoms, hydroxyalkyl esters,    nitriles and amides of α,β-unsaturated carboxylic acids,    the sum of the mass fractions of components B1 to B3 necessarily    being 100%, and the ratio of the mass of the monomer mixture A to    the mass of the monomer mixture B is from 50:50 to 95:5, preferably    from 60:40 to 90:10.

The copolymers AB obtainable in this way preferably contain, based onthe mass of the solids of the dispersion, from 0.2 to 1.7 mol/kg ofcarbonyl groups and from 0.15 to 1.6 mol/kg of carboxyl groups. Themolar amount of the carboxyl groups here is always lower than the molaramount of the carbonyl groups; preferably, the ratio of the molar amountof the carboxyl groups n(-COOH) to the molar amount of the carbonylgroups n(>CO) is from 0.5 to 0.95 mol/mol, with particular preferencefrom 0.75 to 0.9 mol/mol.

The resulting dispersions of the copolymers AB are neutralized followingthe polymerization by adding ammonia, amines or aqueous alkalis, theamount in which the neutralizing agents are added being such that it issufficient to neutralize from 0 to 120% of the carboxyl groups present.

To the dispersion neutralized in this way there are subsequently addedcompounds C having at least two hydrazine or hydrazide groups permolecule, in an amount such that the ratio r of the sum of the molaramount of hydrazine groups n(-NH—NH₂) and the molar amount of thehydrazide groups n(-CO—NH—NH₂) to the molar amount of the carbonylgroups n(>CO) is from 0.5 to 1.1 mol/mol, preferably between 0.8 and 1.0mol/mol.

The copolymer dispersions used in the present invention may be preparedby a process in which water, with or without emulsifiers, is introducedas initial charge and heated to the desired reaction temperature, amixture comprising water, emulsifiers if desired, the monomer mixture A,and a free-radical polymerization initiator is metered in to thisinitial charge, the polymerization is continued until at least 95% ofthe monomers have reacted, then a second mixture comprising water,emulsifiers if desired, and also the monomer mixture B and a furtherfree-radically acting polymerization initiator is metered in and thepolymerization is subsequently continued until the residual monomercontent has fallen below 1%. The resulting dispersion is cooled andadmixed, with stirring, with the neutralizing agent, preferably in theform of an aqueous solution. Subsequently, the hydrazine compound orhydrazide compound C is added with stirring to the neutralizeddispersion of the copolymer AB to form the self-crosslinking dispersionABC.

The amines or alkalis used if desired for neutralization improve thestability of the aqueous copolymer dispersions.

Olefinically unsaturated monomers containing carbonyl groups areemployed as monomer component A1. Preference is given to the use oflinear, branched and cyclic aliphatic compounds having 4 to 20 carbonatoms and each containing at least one carbonyl group and one ethylenicdouble bond. To a minor extent (up to 10% of the mass of the monomersA1) it is also possible to employ compounds having two or morepolymerizable double bonds, which leads to crosslinking of thecopolymer. Particular preference is given to the use of α,β-olefinicallyunsaturated monomers such as N-diacetone(meth)acrylamide and(meth)acrylic acid acetoacetoxyalkyl esters whose alkylene group isselected from 1,2-ethylene, 1,2- and 1,3-propylene, 1,4-butylene and1,6-hexylene and also 1,5-(3-oxa)pentylene and 1,8-(3,6-dioxa)octylenegroups, especially the ethyl esters.

The monomers A2 are preferably α,β-olefinically unsaturated carboxylicacids having 3 to 4 carbon atoms, such as acrylic acid, methacrylicacid, crotonic and isocrotonic acid and also vinylacetic acid.Monoesters of α,β-unsaturated carboxylic acids with linear, branched orcyclic alcohols having 1 to 15 carbon atoms can also be employed, thedicarboxylic acids preferably having 4 to 6 carbon atoms. Preference isgiven to monomethyl and monoethyl esters of maleic acid, fumaric acid,and also citraconic, mesaconic, itaconic and glutaconic acid.

Of the monomers A3, preference is given to the esters of methanol,ethanol, n- and isopropanol with acrylic and methacrylic acid and to thediesters of said alcohols with the dicarboxylic acids specified underA2, and also to n-butyl methacrylate and, of the vinylaromaticcompounds, especially styrene, p-methylstyrene and the isomer mixtureknown as “vinyltoluene”. Particular preference is given to methyl andethyl (meth)acrylate, n-butyl methacrylate, styrene, and dimethylmaleate.

As monomers A4 it is preferred to employ the esters of n-, sec- andtert-butanol, the isomeric pentanols and the higher alcohols such asn-hexanol and 2-ethylhexyl alcohol with α,β-unsaturated carboxylic acidsselected from acrylic and methacrylic acid, vinylacetic acid, maleicacid and fumaric acid; in the case of the dicarboxylic acids referredto, the diesters are used, and n-butyl methacrylate is excluded.

As examples of the hydroxyalkyl esters of olefinically unsaturatedcarboxylic acids as monomer component A5 mention may be made ofhydroxyethyl and 2-hydroxypropyl (meth)acrylate, (meth)acrylonitrile,(meth)acrylamide and, for the vinyl esters, of vinyl acetate.

In the second stage of a polymer having a different chemical structureis produced by adding the monomer mixture B alone or together with newinitiators.

The monomers B1 correspond to those specified under A3, the monomers B2to those specified under A4, and the monomers B3, finally, to thosespecified under A5. The monomer mixture B is therefore free fromcompounds having functional groups selected from carbonyl and carboxylgroups.

The compounds C with hydrazine or hydrazide functionality comprise twoor more hydrazine or hydrazide groups and preferably have an averagemolar mass (M_(n)) of less than 1000 g/mol. Examples of such compoundsare bishydrazides of dicarboxylic acids having 2 to 12 carbon atoms suchas the bishydrazides of oxalic acid, malonic acid, succinic acid,glutaric acid, adipic acid, pinalic acid, suberic acid, azelic acid,sebacic acid or the isomeric phthalic acids; carbonic bishydrazide,alkylene- or cycloalkylene-bissemicarbazides, N,N′-diaminoguanidine,alkylene-bishydrazines such as N,N′-diaminopiperazine,arylenebishydrazines such as phenylene- or naphthylenebishydrazine, andalkylenebissemicarbazides. Compounds C of higher functionality are, forexample, the hydrazides of nitrilotriacetic acid or ofethyl-enediaminetetracetic acid.

Suitable such aqueous acrylic copolymer dispersions can be prepared asknown in the art or may be obtained commercially. The aqueous acryliccopolymer dispersions may be essentially completely acrylic, or maycontain acrylic functionality in combination with other polymerizablematerials, e.g. in the case of aqueous acrylic-modified polyurethanedispersions. Suitable commercial dispersions are available from examplefrom Solutia, under the tradename VIACRYL. For example, VIACRYL 6286, aself-crosslinking, aqueous copolymerisate dispersion containing acrylicesters, may be used in the invention. VIACRYL 6295 may also be used.Additional aqueous copolymer dispersions that may be used includeself-crosslinking acrylic modified polyurethane dispersions availablefrom Alberdingk and Boley under the tradenames MAC 25, MAC 34, MAC 35,and MAC 36; acrylic emulsions available from Alberdingk and Boley underthe tradenames AC548 and AC2538; an acrylic modified polyurethanedisperions available from Alberdingk and Boley under the tradename APU1062; and aqueous acrylic dispersions available from Avecia under thetradenames Neocryl A6015, A633, A6069, XK12 and XK220.

Preferred aqueous dispersions will contain acrylic copolymer resinshaving a glass transition temperature (T_(g)) (prior to the crosslinkingor cure of the inventive compositions) in the range of about −45° C. toabout 40° C. More preferably, the acrylic copolymer resin will have aT_(g) of less than about 25° C., for example about 5° C. to about 25° C.Most preferably, the acrylic copolymer resin will have a T_(g) of lessthan about 15° C., for example about 8° C. to about 15° C.

Generally, the outer layer formed by the aqueous copolymer dispersionwill have a thickness in a range of about 0.5 mils to about 3 mils, moretypically from about 0.8 mils to about 1.2 mils. Oftentimes the aqueouscopolymer composition will contain a coloring agent to impart color tothe outer layer of the product. Additionally, the outer layer formed bythe aqueous copolymer dispersion may be applied to cover a single sideof a finished article (e.g. a skin), or may be applied to the entiresurface of a three-dimensional mold so as to completely coat and therebyencapsulate the molded polyurethane product (e.g. in the case of amolded polyurethane foam ball or toy).

After application, the aqueous copolymer dispersion, preferablyself-crosslinking, may be allowed to partially or fully cure prior topassage of the polyurethane composition into the mold. Preferably, thepolyurethane composition is provided into the mold about 20 seconds toabout 5 minutes, more typically about 20 seconds to 2 minutes after theaqueous copolymer dispersion is applied to the mold surface. Thepolyurethane composition may be applied for example while the aqueouscopolymer dispersion is partially cured or fully cured.

The inner polyurethane layer, often a foamed or cellular (includingmicrocellular) substrate, will be formed by spraying or otherwiseapplying a rapidly reacting composition into the mold and into contactwith the surface coating of the aqueous copolymer dispersion. Typically,the rapidly reacting composition contains at least one aromaticpolyisocyanate and at least one polyol, which react with each other toform the polyurethane inner layer. This polyurethane inner layer isusually non-light-stable, and possesses elastomeric properties such thatthe elastomer layer substantially recovers its original dimensions aftercompression. The aromatic polyisocyanate may also optionally react withone or more components in the aqueous acrylic dispersion, for examplecomponents having free hydroxyl groups, such as hydroxylated acrylicesters. This reaction may be useful in chemically bonding the innerlayer to the outer layer formed from the aqueous acrylic dispersion.

The present invention is also useful in the preparation of multilayerskins, for example by open-mold spray elastomer processes, or so-called“RIM skin” processes. The resulting skins can then be incorporated ascoverings for instrument panels, door panels, seating, or othervehicular components and especially automotive interior components. Inopen mold spray elastomer processing, the aqueous copolymer dispersionis spray-applied to an open mold, optionally after applying a moldrelease agent. Thereafter, a sprayable polyurethane elastomer isspray-applied overtop the aqueous copolymer dispersion. The resulting,cured skin can then be removed from the mold and transferred to anotheroperation (e.g. molding) for incorporation into a finished part.Alternatively, the skin may be retained in the mold, and additionalprocessing conducted in the mold, for example the application of apolyurethane foam, and a substrate, to provide a finished part.Similarly, skins can be prepared by a reaction injection molding (RIM)process in which the aqueous copolymer dispersion is applied to a moldsurface (optionally after application of a mold release agent), andthereafter a rapid curing polyurethane composition injected into themold to form the “RIM skin”. This skin can then be processed into afinished, automotive interior component. Skins prepared in accordancewith the invention by open-mold spray elastomer, RIM skin, or otherprocessing techniques will desirably have a polyurethane layer thicknessof about 0.5 to about 2 millimeters, more preferably about 1 millimeter.Further, the elastomeric skin layer will preferably have a density ofless than 1000 kg/M³, a Shore A durometer hardness of less than 86, atensile strength of greater than 8.8 MPas and/or a tear strength ofgreater than 40 kn/m. The layer thickness resulting from the aqueousdispersion will typically be about 0.5 to about 2 mils, more preferablyabout 0.8 to about 1.2 mils.

For the purpose of illustrating one embodiment of the invention,description will now be made of the in-mold-coating and reactioninjection molding of one exemplary automotive interior part (a steeringwheel) in accordance with the invention.

A covered steering wheel may be manufactured using a molding apparatusincluding first and second portions for forming the back and frontsections of the steering wheel, respectively. The first and second moldportions define therebetween an annular cavity formed by their cavitywalls and a gate(s) leading to the cavity when they are joined togetheralong a parting line. The first and/or second mold portions may have oneor more vent holes formed in its final filling portion which is the lastportion to be filled with the polyurethane material.

A material injection mechanism is provided, for injecting the rapidlyreacting polyurethane composition into the annular cavity through thegate(s). The mixing head may have a first component or set of componentsfor mixing the materials for preparing the inner-layer-formingpolyurethane material (usually a non-light-stable material), and can mixa polyol component, an isocyanate component and any additionalcomponents desired.

The process embodying this invention using the above-described moldingapparatus will now be described in the order of its steps for themanufacture, by a reaction injection molding (RIM) process, of atwo-layer composite for covering a steering wheel.

The first and second mold portions of the mold are separated from eachother, and a mold release agent (when used) is applied, such as byspraying, to the cavity walls. Where the aqueous copolymer dispersioncontains an appropriate amount of mold release agent, or is otherwiseformulated so as not to require the use of a release agent, this step ofapplying the mold release agent can be omitted. The aqueous copolymerdispersion is then applied to the cavity walls, such as by spraying, toform a film adhering to substantially the entire surfaces of the cavitywalls. The aqueous dispersion will also be applied in an amountsufficient to provide the desired cured film thickness for the outer,decorative and/or protective layer of the automotive interior component.

A metal core for a steering wheel is set in the first or second moldportion, and the mold portions are joined together to form the cavity.The components of the mixing head dedicated to the inner polyurethanematerial are used to combine the polyol component, the isocyanatecomponent, and any other desired components of the material. Thepolyurethane material is injected through the gate so as to fill thecavity surrounding the metal core and contact the film formed from theaqueous dispersion. After curing, the first and second mold portions areseparated from one another, the coated automotive steering wheel isremoved from the mold, and any flash is removed, to provide the finishedcomponent. With reference to FIG. 1, the resulting in-mold-coatedsteering wheel 10 has an outer layer or covering 11 formed by theaqueous copolymer dispersion and adhered to the inner polyurethane layer12, both of which cover the metal core 13 of the steering wheel 10.

In accordance with one embodiment of the invention, multiple aqueousdispersed compositions containing different coloring agents can beapplied to different portions of the automotive interior article toproduce discretely masked colors. It has been discovered that suchprocesses can be conducted wherein subsequent aqueous dispersions can beapplied to previously-applied dispersion while still wet, enabling forexample wet-on-wet (WOW) and wet-on-wet-on-wet (WOWOW) processing.

The optional additives in the aqueous-dispersed composition used to formthe outer layer can include, without limitation, any combination of thefollowing: heat and ultra-violet light stabilizers, pH stabilizers tomaintain an alkaline state of dispersion, plasticizers, antioxidants,dulling or flatting agents, surfactants, colloidal protectants tomaintain particles in suspension, flow additives, colorants such asorganic and inorganic pigments, carbon black, thixotropic agents (e. g.,hydroxy methyl cellulose), abrasion resistance agents such as waxdispersions, and fillers such as clay particles.

The overall aqueous-dispersed composition can contain, for example,about 15% to about 60% resin solids by weight, more preferably about 20%to about 50% resin solids by weight, and about 85% to about 40% water byweight, more preferably about 80% to about 50% water by weight. Theaqueous-dispersed composition may also contain smaller amounts oforganic solvents, for example up to about 10% solvents by weight, e.g.about 0.5% to about 10% solvents by weight, depending on desired color,additives, and other similar factors. Compositions of the invention mayinclude one, two, or more curable resins as described herein, and inadvantageous such embodiments include no external crosslinking agents(i.e. crosslinking of the composition is achieved by one or more of thecurable resin components). In particularly preferred aspects of theinvention, the overall aqueous-dispersed composition will constitute aone-component composition, thus having only a single curable resincomponent, potentially combined with other conventional additives asdisclosed herein.

Preferred overall aqueous acrylic coating compositions used in theinvention will also contain no or only low levels of higher boilingsolvents that are slow in evaporating from the film applied to the moldsurface and are deleterious to the outer coating and/or innerpolyurethane layer. For example, commercial aqueous polyurethanedispersions commonly contain substantial levels of n-methylpyrrolidinone (NMP), which evaporates very slowly from applied films. Asa result, mold temperatures must be increased, if possible, and/orlonger solvent flash times are necessary, to remove NMP from the filmthat would otherwise cause undesirable blistering of the outer coatinglayer of the vehicular component. Preferred overall aqueous coatingcompositions will thus include no greater than about 10% organic solventhaving a boiling point in excess of about 180° C. and/or an evaporationrate less than 0.03 (where n-butyl-acetate=1), more preferably no morethan about 5% by weight of such solvent(s), and most preferably no morethan about 3% by weight of such solvent(s). Preferred overall aqueouscoating compositions used in the invention will contain no more thanabout 2.5% by weight NMP, more preferably no more than about 1% byweight NMP, and will most preferably be free or essentially free of NMP.

Exemplary polyisocyanates that can be selected for the polyurethanecomposition employed to prepare the inner layer include both aromaticand aliphatic diisocyanates, including diisocyanates having aromaticclosed-ring structures, such as diphenylmethane diisocyanate prepolymer(MDI prepolymer), which can be obtained from BASF Corp. of Wyandotte,Mich. under the trade designation ELASTOLIT M50555T, ISOCYANATE, NPUU05275, or diphenylmethane-4,4′-diisocyanate (MDI), or mixed isomers ofMDI or mixtures of the above, which are available from BASF or DowChemical Corp. of Midland, Mich., Mobay (Bayer) Chemical Corp. ofBaytown, Tex., or ICI America of Geismar, La. The above-mentionednon-light-stable aromatic polyisocyanates are very desirable for use inthe inner layer in view of the higher rate of reactivity and completionof property development and better physical properties (e. g., tensilestrength, elongation, and tear strength) of these non-light-stablearomatic polyisocyanate when compared to light-stable aliphatic-basedisocyanates such as isophorone diisocyanates, in which the-NCO groupsare sterically hindered due to their spatial arrangement at either endof the molecule. By contrast, the aromatic diisocyanates used in thisinvention preferably have —NCO groups directly attached to the aromaticring. In this preferred embodiment, the aromatic diisocyanates yieldfaster rates of reaction because of the arrangement and reactivity ofthe-NCO groups on the aromatic ring structure (e. g., in diphenylmethanediisocyanate) and the availability of the-NCO groups for reaction withthe hydrogen donors of the-OH type residing on the organic chain of thepolyols of the rapidly reacting composition.

Suitable polyols for the rapidly reacting composition include, withoutlimitation, polyether polyols having average molecular weights in arange of from about 200 to about 2000 and containing one or more pendenthydroxyl and/or carboxyl groups in addition to primary hydroxyl groupswhich can chemically react with unreacted functional —NCO groups of theblocked, heat-activated aliphatic diisocyanate. An exemplary polyol isELASTOLIT M50555R NPU U05274 from BASF Corp. of Wyandotte, Mich.

The rapidly reacting composition can also contain appropriate additives,including, by way of example and without limitation, any combination ofthe following: heat and ultraviolet light stabilizers, pH stabilizers,antioxidants, dulling agents, surfactants, carbon black, chain extenders(e. g., ethylene glycol), thixotropic agents (e. g., amorphous silica),fillers such as clay particles, and catalysts such as tin catalysts (e.g., dibutyltin dilaurate).

Various blends of polyether polyols and polyisocyanates having suitableresilience properties can be employed to form the polyurethane innerlayer. For example, the polyisocyanate blend can include methylenediisocyanate. The polyurethane of the inner layer can also containappropriate additives, including, by way of example and withoutlimitation, any combination of the following: surfactants, antioxidants,fillers, stabilizers, catalysts such as tin catalysts (e. g., dibutyltin dilaurate) and amines (e. g., diethanolamine), and small amounts offoaming agents such as water. In this regard, it is noted that in someembodiments of the present invention, the condensation reaction betweenthe blends of polyols and polyisocyanates releases water, which reactswith the polyisocyanate to generate carbon dioxide and thereby impartthe cellular structure to the inner polyurethane layer. Accordingly, aslightly stoichiometric excess of polyol can be provided to form asemi-rigid polyurethane cellular foam when desired.

Additional information regarding compositions that are useful in formingthe inner layer of skins and the like is found in United States PatentPublication No. 2002001722 A1 dated Jan. 3, 2002 and publishing U.S.patent application Ser. No. 09/124,328 filed Jul. 29, 1998, which ishereby incorporated herein by reference.

The rigid core or substrate of the automotive interior component can beselected from any material possessing the requisite strength toreinforce and mount the outer layer and inner layer. Suitable materialsinclude polyolefins, such as polypropylene and ethylene-propylenecopolymers, thermoplastic olefins (TPOs), and thermoplastic polyolefinelastomers (TPEs). In some instances where even higher levels ofperformance are required, engineering thermoplastics may be selected.These include injection molding thermoplastics, such as acrylonitrilebutadiene styrene (ABS), polycarbonate (PC), a PC/ABS alloy,thermoplastic polyurethane (TPU), styrene maleic anhydride (SMA), andreaction injection molded polyurethanes (RRIM). Other materials, such asmetals, metal alloys, wood-fiber composites, or any combination thereof,can also be used.

Although the method of the present invention has been embodied above inconnection with the preparation of a steering wheel, it is understoodthat the method is equally applicable to other structures, including forexample panel structures, e.g. instrument panels, armrests, headrests,floor consoles, knee bolsters, airbags and glove compartment doors.

For the purpose of promoting a further understanding of the presentinvention and its features and advantages, the following specificExamples are provided. It will be understood that this Examples areillustrative, and not limiting, of the present invention.

Example 1 Preparation of In-Mold Coating

A coating composition was prepared having the following formulation:

a. Viacryl 6286 66.55%  (aqueous copolymerisate dispersion comprised ofacrylic esters and a small amount of styrene) b. Microspersion 1902.51%  (wax dispersion providing abrasion resistance) c. Pergopak M31.40%  (flattener) d. Water 27.95%  e. Secondary n-Butanol .56% f.Acrysol RM825 .18% (thickening agent) g. Surfynol 104BC .84% (flowadditive)

Color was added using a universal tinting system available from Red SpotPaint & Varnish Co., Evansville, Ind., U.S.A.

The above composition was prepared by adding the Viacryl 6286 resin to aclean formulation tank, and then sifting in the Microspersion 190 underagitation and mixing for 15 to 20 minutes. Care was taken to be surethat the wax dispersion was dispersed and exhibited no settling beforeit addition. The Pergopak M3 flattener was then sifted in underagitation, and cut in for 30 minutes to ensure proper dispersion. Thewater and butanol were premixed together in a separate container, gentlystirred, and then added to the formulation tank. The Acrysol RM 825 andSurfynol 104 BC were then slowly added under agitation, and mixing wascontinued for 15 to 20 minutes. Red Spot's Universal Tints were addedfor color.

The resulting composition is highly useful for in-mold-coatingapplications to form outer decorative and/or protective layers ofmultilayer composites for covering automotive interior components. Thematerials in particular demonstrates excellent adhesion to innerpolyurethane layers of such components.

The invention has been described above in detail, with specificreference to its preferred embodiments. It will be understood, however,that a variety of modifications and additions can be made to theprocedures disclosed without departing from the spirit and scope of theinvention. Such modifications and additions are desired to be protected.In addition, all publications cited herein are indicative of the levelof skill in the relevant art, and are each hereby incorporated byreference each in their entirety as if individually incorporated byreference and fully set forth.

What is claimed is: 1-29. (canceled)
 30. A method of manufacturing acoated, molded polyurethane elastomer product, comprising: providing amold for making the product, the mold having a mold surface; coating themold surface with an in-mold coating composition, said in-mold coatingcomposition comprising a self-crosslinking, aqueous copolymerdispersion; passing a polyurethane elastomer composition into the moldand into contact with the in-mold coating composition; and causing thein-mold coating composition and polyurethane elastomer composition tocure, so as to form a coated, molded polyurethane elastomer product.